Exposure to traumatic events may lead to mental health problems such as posttraumatic stress disorder (PTSD), a debilitating condition with potentially costly implications for the individual and society. Homeless women suffer from traumas and PTSD at rates typically higher than among housed women. Although effective, empirically validated treatments for PTSD are available, homeless women are unlikely to avail themselves of mental health services despite high levels of need. The three-year study proposed here addresses a critical gap in treatment research to meet the mental health service needs of homeless women. The Specific Aims of this study correspond with three phases of activities: Aim 1/Phase 1: Gather and analyze information on the context of PTSD and PTSD treatment for homeless women ages 18 and older through a) focus groups with homeless women having symptoms of PTSD (2 groups, 6-8 persons per group), and b) focus groups with shelter directors, case managers, and providers of mental health and other services to homeless women (2 groups, 6-8 persons per group). Aim 2/Phase 2: Develop an adaptation of an existing cognitive behavioral therapy (CBT)-based PTSD treatment manual to make it relevant for the lives of homeless women based on a) findings from Aim 1/ Phase I focus groups, and b) ongoing advice and feedback from homeless women (2 sets of 2 focus groups, 6-8 women per group), and shelter directors, case managers, and providers of mental health and other services to homeless women (2 sets of 2 focus groups, 6-8 persons per group). Aim 3/Phase 3: Conduct a pilot test of the adapted intervention with homeless women who have symptoms of PTSD. We propose a randomized design in which 32 women, 16 in each of two participating shelters, will be assigned to either the PTSD intervention condition or to an assessment-only control condition during the study intervention period. [unreadable] This study will culminate in Year 3 with several products: 1) a PTSD intervention and manual adapted for use with homeless women in shelter settings, 2) pilot data on intervention implementation and variation in outcomes that allow power analyses for key outcomes, 3) two scholarly journal publications and a conference presentation, and 4) a plan for an R01 application to test the efficacy of the PTSD intervention. [unreadable] [unreadable]